As various types of contents increase and high-capacity contents, such as High Definition (HD) contents, Ultra High Definition (UHD) contents, increase, data congestion becomes worse over a network. Due to the situation, the contents that a transmitter sends is not normally transferred to a receiver, and a part of the contents is lost on route. In general, data is transmitted based on a packet unit, and the data loss occurs based on a packet unit. Accordingly, the receiver fails to receive a packet due to the data loss on the network, and thus, may be unaware of the data in the lost packet. Therefore, it may cause deterioration of audio quality, degradation of video image quality or an image breaking, an omission of a subtitle, a loss of a file, and the like making an inconvenience for a user. Due to the above reasons, there is a desire for a method of restoring the data loss occurring on the network.
As one of the methods, raptor codes may be used, which is one of the channel coding methods, and has an advantage of freely adjusting a code rate which indicates a ratio of an amount of encoded data to existing information. The raptor code operates based on a block unit, and has the advantage of randomly selecting source symbols and generating a huge amount of encoded symbols. The raptor code may execute complete decoding without an error when a predetermined amount of encoded symbol is received, irrespective of the order of reception or a loss. A method of determining a code rate in consideration of a wireless network state, using the raptor code, a scheme of transmitting data encoded based on the determined code rate over a network, and the like have been provided.
However, the conventional technologies do not consider the selection of an effective parameter of a raptor code. The complexity of the raptor code is significantly changed based on a parameter, and may also be changed based on the performance of a device implementing the same. Also, the parameter may need to be changed dynamically based on a network state. When the parameter is inappropriately selected, effective network transmission may be impossible.